The American Dipper in Colorado 5 



bird differ in shape to suit the cavities in which they are placed, but the front 

 is always oven-shaped. The one before me partakes of the shape of the crevice 

 in which it was placed and measures exteriorily seven inches high, eight inches 

 long and seven inches broad. The oustide covering is about one and one-fourth 

 inches thick above the rim of the inside nest and about two inches thick below 

 the rim and beneath the nest. This covering is composed chiefly of moss, with 

 some decayed leaves and other rubbish, evidently taken from the water, with 

 bark and grass fiber securing it together, and is always dense, dank and wet 

 from the spray of the dashing water. The entrance is a small aperture, about 

 one and one-half inches in diameter, placed about four inches from the bottom 

 and cleverly hidden by the ragged material of the outer construction hanging 

 over it. The direction of entrance by the bird is upward and its exit downward, 

 as with the Cliff Swallow. The nest proper, concealed by the outer structure 

 and about two inches from the outside edge thereof, is a beautiful structure, 

 a perfect circle, saucer-shaped, about an inch and a half deep and three and 

 one-half inches wide inside the cup. This is composed of a peculiar, non-absor- 

 bent, coarse, wiry grass, lined with a few willow leaves, flat and intact, all per- 

 fectly dry. All materials being used wet, after they are worked into position and 

 molded by the bird's body being twirled around, the nest proper remains a fixture. 

 This nest-wall of grasses is about one inch thick. The nest inside in shape and 

 material seems always to be the same. The material entering into the construc- 

 tion of the covering is chosen to match the site it is intended to occupy. Moss 

 is sometimes ignored, and decayed and other debris and rubbish substituted 

 to keep the outside in harmony with its surroundings. The whole structure 

 in place is scarcely distinguishable from the surroundings, all being of the same 

 color and having the appearance of a bunch of debris placed there by high 

 water — nothing new-looking about it. It is very compact and strong, so little 

 damaged as a rule by a season's occupation and the wear and tear of the winter's 

 storms that very little repair is needed for a second year's occupancy. Decay 

 of the materials after a time causes the dome to sink down, thereby rendering 

 it inconvenient if not entirely useless. Then it is pulled down and a new one 

 built on the same site. I have known of a pair of the birds, no doubt the same 

 pair, building in the period of eight years several nests as occasion required 

 in the same niche. 



"May n, 1893. Both birds at work on the nest, probably five days' work 

 done. In shape like a horseshoe, open end back by an upright rock ledge. 



"May 19, 1893. Nest noted on the eleventh instant, in a period of two weeks 

 very little done on it, not more than two fair days' work as I saw the female 

 working this morning for an hour while the sun was bright and warm. In every 

 minute or two she brought material and incorporated it into the walls of the 

 nest dome in the most ingenious manner, by forcing, with much exertion of 

 her bill, the fresh wet material into the interstices in the already constructed 

 and partially dry walls, from the inside, as a shoemaker uses his awl, picking 



